Thin polished plates such as silicon wafers and the like are a very important part of modern technology. A wafer, for instance, may refer to a thin slice of semiconductor material used in the fabrication of integrated circuits and other devices. Other examples of thin polished plates may include magnetic disc substrates, gauge blocks and the like. While the technique described here refers mainly to wafers, it is to be understood that the technique also is applicable to other types of polished plates as well. The term wafer and the term thin polished plate may be used interchangeably in the present disclosure.
In the course of manufacturing a semiconductor device, a wafer goes through hundreds of processing steps to pattern a functioning device. Over the course of these steps, inspection and metrology steps are performed to ensure the process is in control and will produce functioning product at the end of the manufacturing cycle. Inspection tools may find unintended defects in the patterning whereas metrology tools may measure the physical parameters of the films and patterns versus the intent. While some defects and metrology errors may be so significant as to clearly indicate a device failure, lesser variations may have an unclear effect. A portion of these may later go on to cause early reliability failures of the device after exposure to their working environment. Risk averse users of semiconductor devices, such as automotive, military, aeronautical and medical applications, need failure rates in the Parts per Billion (PPB) range, well below where they are today. Recognizing and controlling these so-called latent reliability defects is key to meeting these industry requirements. Therein lies a need for providing the methods and systems for latent reliability defect detection.